Field of the Invention
The invention generally relates to wireless communication transceivers, and more particularly to mobile communication devices and methods for controlling wireless transmission and reception with nano-deactivation of a reception circuit and/or a transmit circuit.
Description of the Related Art
In an Orthogonal Frequency Division Multiplex (OFDM) system, uplink/downlink signal transmission is made on a subframe basis and one subframe is defined by a certain time interval including a plurality of OFDM symbols. The Third Generation Partnership Project (3GPP) supports a type 1 radio frame structure applicable to Frequency Division Duplex (FDD), and a type 2 radio frame structure applicable to Time Division Duplex (TDD). Take the Long Term Evolution (LTE) technology as an example. As shown in FIG. 1, each LTE frame structure includes 10 subframes, and each subframe consists of 2 timeslots, each of which includes 6 or 7 OFDM symbols. The modulated symbols are constructed from a data packet and inserted into a rectangular grid of OFDM symbols in the time-frequency domain. This rectangular grid is further divided into the so-called “resource blocks,” such that each resource block includes consecutive sub-carriers in the frequency domain and consecutive OFDM symbols in the time domain. An LTE resource block includes 12 consecutive sub-carriers in the frequency domain and a timeslot of 6 or 7 consecutive OFDM symbols in the time domain.
To coherently demodulate the symbols included in these resource blocks, an OFDM receiver must estimate the channel over which the resource blocks are received. To facilitate this estimation, Reference Signal (RS) symbols (also referred to as pilot symbols) are transmitted in each resource block. In the LTE technology, an RS may be a Cell-specific RS (CRS), a Multicast-Broadcast Single Frequency Network (MBSFN) RS, a User Equipment (UE)-specific RS associated with Physical Downlink Shared Channel (PDSCH), a De-Modulation (DM) RS associated with Enhanced Physical Downlink Control Channel (EPDCCH), a Positioning RS, or a Channel State Information (CSI) RS. Generally speaking, the response of the wireless channel in an OFDM system is a slow-varying, two-dimensional function of time and frequency. Accordingly, RS symbols need not be placed in every subcarrier nor in every OFDM symbol interval. Instead, RS symbols may be sparsely distributed across each resource block.